Mariana Trench: historic ocean dive repeated

Kelly Walsh, the son of the great ocean explorer Don Walsh, has descended to the bottom of the Mariana Trench, almost 11km down in the Pacific. He made the dive 60 years after his father created history in doing so.

The 12-hour dive on Saturday saw him reach a depth of approximately 10,925m, according to the BBC.

Walsh described it as “a hugely emotional journey” after returning to the surface.

The descent was piloted by the financier and adventurer Victor Vescovo. The Texan is conducting a series of dives into the lowest point of the Mariana Trench known as the Challenger Deep.

Vescovo has acquired a support ship and human-rated submersible that he is using to survey several of the most extreme places on the ocean floor.

Recent passengers who’ve gone down with him to the Challenger Deep include former Nasa astronaut Kathy Sullivan, and British-American mountaineer Vanessa O’Brien.

But Kelly Walsh’s descent is noteworthy because of his father, Don. On 23 January, 1960, the then US Navy officer, accompanied by Swiss national Jacques Piccard, made the first crewed dive to the floor of Earth’s deepest ocean trench using the bathyscaphe Trieste.

It was an astonishing achievement. The trench is so deep, it would be possible to fit Mount Everest (8,848m) inside it and still have more than 2km of water above the peak. The pressure at the trench floor is crushing – some 100 million pascals, almost 16,000 pounds per square inch.

Sixty years on, modern technology means Victor Vescovo can reliably make very safe, repeat dives, so much so that he himself has now been down six times in his submersible, the 12-tonne Deep Sea Vehicle (DSV) Limiting Factor.

On Saturday, Vescovo and Walsh spent fours hours at the bottom of what’s called the ‘western pool’ – one of three distinct zones in the Challenger Deep. It’s the same pool that Don Walsh and Piccard visited, and the latest dive marked the first time anyone had been back since, says the BBC.